- Microsoft confirmed a false “Microsoft Defender Antivirus is turned off” warning, even when Defender is working correctly.
- The Defender problem affects multiple Windows and Windows Server versions and will be fixed through a future Defender update.
- Windows 11 24H2 and 25H2 users report custom mouse cursors and animations reverting after KB5120998 and later updates.
Microsoft is warning users about two new problems affecting Windows 11 following recent updates. One issue is causing incorrect notifications claiming that Microsoft Defender Antivirus is turned off, even when the antivirus is running normally. The other is affecting users by resetting customized mouse cursor settings.
The two problems appear to be unrelated. The company has confirmed the Defender issue and says it’s working on a fix, while it’s still looking into the mouse customization problem.
Defender false alert
The Defender problem is the more widespread of the two. According to the software giant, the incorrect notifications can appear on any supported version of Windows or Windows Server running Microsoft Defender Antivirus with the latest Defender updates installed. The warning can appear when the operating system starts and intermittently afterward, and it can continue appearing even when notification settings have been disabled.
Importantly, Microsoft says the notification does not necessarily mean that Defender Antivirus has actually been disabled. The antivirus can remain fully operational while the system incorrectly reports that it’s turned off.
Microsoft is working on a resolution that will be delivered through a future Microsoft Defender Antivirus update. The company has not provided a release date for the fix.
Mouse cursor missing
The second problem is more specific to Windows 11. Microsoft has received reports that mouse cursor personalization settings can be lost or reverted to standard settings after installing the latest preview of the September 2026 update KB5120998 and later updates.
Affected users have reported appearance changes involving customized mouse cursors and animations. In some cases, high-DPI cursors can reportedly be replaced with larger white cursors, while custom cursor animations can revert to their default settings. Some users have also reported that restoring their previous cursor configuration does not resolve the problem.
Microsoft is currently looking into whether the mouse customization problem is caused by an update. Unlike the Defender issue, the company has not yet confirmed the cause or announced a fix.
For now, the software giant recommends that affected users submit reports through the Feedback Hub. The app can be opened by pressing the “Windows + F” keyboard shortcut.
The two problems affect different sets of Windows versions, so users should not assume that experiencing one means their system is affected by the other. The Defender notification problem has a much broader scope, while the mouse customization problem is currently limited to Windows 11 24H2 and 25H2.
Microsoft says it will provide additional information as it investigates both issues.
Pureinfotech’s Take
I’m not too concerned about the antivirus warning itself as long as the antivirus remains active, but I understand why this kind of notification can cause unnecessary panic. Security warnings are one area where the system really needs to get it right because most users won’t know whether a notification is a false alarm or a sign their device is actually unprotected.
Have you experienced either of these Windows problems?
Voting closes: September 7, 2026 1:00 pm
The mouse problem bothers me more from a usability standpoint. People who customize their cursor usually do it for a reason, and having the operating system unexpectedly undo those settings is the kind of small regression that can make an otherwise uneventful update frustrating. I’d be cautious about installing optional updates when I don’t need the fixes or improvements they provide, especially when Microsoft is still working on these problems.
Have you run into either of these problems after updating Windows? Let me know in the comments.
Mauro Huculak is a Windows How-To Expert and founder of Pureinfotech in 2010. With over 23 years as a technology writer and IT Specialist, Mauro specializes in Windows, software, and cross-platform systems such as Linux, Android, and macOS.
Certifications: Microsoft Certified Solutions Associate (MCSA), Cisco Certified Network Professional (CCNP), VMware Certified Professional (VCP), and CompTIA A+ and Network+.
Mauro is a recognized Microsoft MVP and has also been a long-time contributor to Windows Central.
You can follow him on YouTube, Threads, BlueSky, X (Twitter), LinkedIn and About.me. Email him at [email protected].
